Unusual Loading-Dependent Sintering-Resistant Properties of Gold Nanoparticles Supported within Extra-large Mesopores

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• 作者：Xiaoqing Yan ; Xiaojuan Wang ; Yu Tang ; Guicen Ma ; Shihui Zou ; Renhong Li ; Xiaogang Peng ; Sheng Dai ; Jie Fan
• 刊名：Chemistry of Materials
• 出版年：2013
• 出版时间：May 14, 2013
• 年：2013
• 卷：25
• 期：9
• 页码：1556-1563
• 全文大小：611K
• 年卷期：v.25,no.9(May 14, 2013)
• ISSN：1520-5002

文摘

Unexpected, excellent antisintering property of highly loaded AuNPs is observed when extra-large mesoporous silica EP-FDU-12 (cage size >25 nm) is used as the supports. The average particle size of the entrapped AuNPs after 550 掳C calcination approaches 25.6 卤 5.2 nm at the gold loading amount of 5.0 wt %, but it greatly reduces into only 5.6 卤 1.2 nm as the metal loading reaches up to 26.1 wt %. It is demonstrated that the unique three-dimensional porous structure of EP-FDU-12 makes particle-migration difficult to occur and thus prevents direct particle鈥損article aggregation. This further allows two or more AuNPs to be encapsulated in every extra-large cage at high particle concentrations (10鈥?5 wt %), which enables interparticle interactions via significant overlapping of the diffusion-spheres of AuNPs. As a result, atom-migration via vapor from cage to cage is largely shut off and local vapor-particle equilibrium within each cage is possible, leading to a successful stable AuNPs/mesoporous silica system.

Keywords:

gold nanoparticle; mesoporous silica; antisintering property; interparticle interaction